[Indigo]<Solidviews>CSG>SVFancyRaysImpl.mesa!11

File: SVFancyRaysImpl.mesa

Created July 3, 1983 12:33 pm

Last edited by Bier on August 5, 1984 1:07:19 pm PDT

Contents: Procedures implementing shadows (reflections and transparency to come).

DIRECTORY

CastRays,

CSG,

IO,

SV3d,

SVFancyRays,

SVModelTypes,

SVRayTypes;

SVFancyRaysImpl: PROGRAM

IMPORTS CastRays, CSG, IO

EXPORTS SVFancyRays =

BEGIN

CSGTree: TYPE = SVRayTypes.CSGTree;

LightSource: TYPE = SVModelTypes.LightSource;

LightSourceList: TYPE = SVModelTypes.LightSourceList;

Point3d: TYPE = SV3d.Point3d;

Ray: TYPE = SVRayTypes.Ray;

Vector: TYPE = SV3d.Vector;

VisibleLights: PUBLIC PROC [allLights: LightSourceList, surfacePoint: Point3d, tree: CSGTree, useBoundSpheres: BOOL, makeStream: BOOL ← FALSE, f: IO.STREAM ← NIL, indent: NAT ← 0] RETURNS [visibleLights: LightSourceList] = {

surfaceToLightRay: Ray;

lightsource: LightSource;

ambient: LightSource;

hits: BOOL;

t: REAL;

IF makeStream THEN f.PutF["\nFinding Visible Lights...\n\n"];

surfaceToLightRay ← CSG.GetRayFromPool[];

visibleLights ← NIL;

IF allLights.first.type # ambient THEN ERROR;

ambient ← allLights.first; -- CONS on last, so it will be first.

FOR l: LightSourceList ← allLights.rest, l.rest UNTIL l = NIL DO

lightsource ← l.first;

CSG.StuffWorldRayFromPoints[surfaceToLightRay, surfacePoint, lightsource.position];

[hits, t] ← CastRays.FirstHit[surfaceToLightRay, tree, useBoundSpheres, makeStream, f, indent];

IF hits THEN {

IF t >=1 THEN visibleLights ← CONS[lightsource, visibleLights]

The first hit occurs past the light source.

}

ELSE visibleLights ← CONS[lightsource, visibleLights];

ENDLOOP;

CSG.ReturnRayToPool[surfaceToLightRay];

visibleLights ← CONS[ambient, visibleLights];

The ambient light is never blocked.

};

END.

Edited on August 2, 1983 5:12 pm, by Bier

Fixed VisibleLights so that a light is considered visible even if a ray from surface to light hits an object, so long as that object is past the lightsource.